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Half of drain trouble is knowing what to attempt; the other half is knowing whose pipe it is. Both halves are posted below.
Notice summary: stop putting water in, make one or two honest attempts, then establish whose pipe it is. Sinks answer to a plunger or hot water and washing-up liquid; toilets to patience and a proper seal. If the neighbours are backing up too, it's likely NI Water's public sewer — report it to them. If it's yours alone, ring 020 4577 2888 and describe what's rising where.
Every drain in the house meets the same pipe, so stop running water into all of them. No washing machine, no dishwasher, no second flush.
A blocked drain never improves under load. The washing machine mid-cycle, the dishwasher, a running tap two rooms away — all of it arrives at the same obstruction and has to go somewhere, and "somewhere" is usually your shower tray or the gully outside the back door. So the first act is restraint: halt the machines, close the taps, and warn the household.
Then take stock like a harbourmaster reading the tide. One slow sink is a local problem in that fixture's own trap — annoying, small, usually yours to win. Several fixtures gurgling and backing up together, or waste appearing at the lowest drain in the house, is a main-drain problem and a different order of job. The distinction decides everything that follows, including who you call.
A plunger with a proper seal, hot (not boiling) water with washing-up liquid on kitchen grease, and emptying the trap under the sink. Two honest attempts, then stand down and ring.
For a greasy kitchen sink, hot water — from the hot tap, not the kettle at a rolling boil, which can distort plastic pipe and traps — carried down with a good squeeze of washing-up liquid softens and moves congealed fat surprisingly often. For standing water, a plunger earns its keep, but only with a seal: block the overflow hole with a wet cloth, seat the cup fully over the plughole, and work it steadily rather than furiously.
The trap — the U-bend under the sink — unscrews by hand with a basin underneath, and a remarkable percentage of blockages are sitting right there in the form of fat, teabags and a teaspoon. Beyond that, a cheap drain snake or even a straightened wire coat hanger can hook hair out of a bathroom waste. What is not worth attempting: dismantling anything beyond the trap, rodding through an inspection chamber without knowing the run, or third and fourth attempts at something that has twice refused — that's when persuasion becomes damage.
Fat, oil and grease; wipes of any description; cotton buds, kitchen roll and hair. The packet may say flushable — the pipe says otherwise.
A word of warning to all households: nearly every blockage a plumber clears was loaded aboard by the household itself, a little at a time. Warm fat poured down a sink sets in the cold pipe like candle wax, narrowing it month by month. Wipes — bathroom, baby, cleaning, "flushable" — do not break down the way paper does; they knit together with the fat into the dense grey rope of the trade's least favourite cargo.
The remedies are almost embarrassingly cheap: a jar or tin by the cooker for fat, a bin beside every toilet, a hair trap in the shower, and a house rule that the toilet takes only the three Ps — pee, poo and paper. Chemical drain cleaner deserves its own caution here: poured onto a blockage that doesn't shift, it leaves a sink full of caustic water for whoever works on the pipe next. Use it sparingly if at all, say so honestly when you ring, and never mix products.
Drains serving only your property, inside your boundary: yours. The public sewer, and generally the shared runs beyond your boundary: NI Water's. The neighbours' symptoms are your evidence.
In Northern Ireland the public sewers are NI Water's charge, and the broad rule runs like this: the drain serving only your own property, within your own boundary, is the householder's responsibility; where drains from several properties combine, and beyond the boundary, responsibility generally passes to NI Water's public sewer. The practical test costs nothing — ask the neighbours. If the houses either side are gurgling, slow and backing up at the same hour you are, the trouble is almost certainly in the shared sewer, and you should report it to NI Water rather than pay privately to clear a pipe that isn't yours.
In the terraced streets near the town centre and harbour, shared runs and old combined drains are common, so this question is worth settling before anyone lifts a cover. Out in the country — Islandmagee, Ballycarry, Straid — many homes are on septic tanks rather than mains drainage at all, which changes the conversation again: a backing-up system with a full tank needs emptying and inspection, not rodding. Either way, say which kind of property yours is when you ring, and the right help arrives first time.
The gully grid by the back door blocks with leaves, moss and silt long before the pipe below it does. Clear the grid by hand first — it settles half of all "blocked drain" alarms.
When rainwater sheets across the yard or a downpipe overflows in weather off the Lough, the culprit is very often sitting in plain sight: the gully grid, dressed in leaves, moss and the grit our damp climate manufactures all year. Rubber gloves, lift the debris clear, scoop what you can from the bowl beneath, and pour a bucket of water through to test the flow. No tools, no mystery, frequently no further problem.
If the gully bowl itself stays full after the grid is clean, the blockage is below ground in the run, and that's rodding territory — a judgement call between a confident householder with a proper set of drain rods (always twist clockwise, or the rods unscrew and stay in the pipe as a souvenir) and the plumber this line can raise. Shorefront properties and exposed coastal houses should give their outside gullies and grids a glance every autumn as a matter of routine; the sea sends the weather, and the weather sends the leaves.
As a broad rule, drains serving only your property and inside your boundary are yours; the public sewer, and in general the shared drains beyond your boundary, are NI Water's. If your neighbours are gurgling and backing up at the same time as you, that points at the public sewer — report it to NI Water rather than paying privately. Trouble in just your house points at your own drain, which is a plumber's job.
Rarely, and never repeatedly. Caustic cleaner sitting on top of a full blockage doesn't clear it — it turns the standing water dangerous for whoever eventually rods or plunges the pipe, you included. Hot water and washing-up liquid on a greasy kitchen sink, or a plunger used properly, does more good with none of the hazard. If two honest attempts fail, stop and ring.
Don't flush again — one rise is a warning, two is a floor to mop. Stop running water into every drain in the house, since it all meets the same pipe. If the bowl is high, wait: a partial blockage often lets the level fall slowly. Then plunge with a proper seal if you're willing, or ring. If more than one fixture backs up at once, that's a main-drain problem, not a toilet problem.
The same cargo the whole country over: cooled fat and grease from the kitchen, wipes of every kind (whatever the packet claims), cotton buds, kitchen roll and hair. Fat poured warm sets solid in the cold pipe like candle wax; wipes knit everything together. None of it belongs in a drain — a bin beside the sink and a hair trap in the shower prevent most of the calls this page exists for.
The main notice — how the line works and the waters it covers.
Go to home →Close the stopcock before all else — the full standing orders.
Read the notice →Pressure, error codes, oil and gas — and the gas standing order.
Read the notice →How charging works and the questions to put before work starts.
Read the notice →Pressure, timer, tripped switch, immersion — checks in order.
Read the notice →Gentle thawing from the tap end, and never with a flame.
Read the notice →Damp patches, slipping pressure and the stopcock test.
Read the notice →Grid cleared, plunger tried, neighbours consulted? If it still won't run, ring any hour and put the facts to a local plumber covering Carrickfergus and the villages around it.
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